diff --git a/README.md b/README.md
index 7c09e02..ceee29b 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,9 @@
+# ⚠️ BETA BETA BETA ⚠️
+
+This `master` branch is suitable for the 1.0 beta release of Ghost, it will **NOT** work with earlier releases.
+
+For a 0.x.x compatible release please checkout the [lts](https://github.com/TryGhost/Casper/tree/lts) branch.
+
 # Casper
 
 The default theme for [Ghost](http://github.com/tryghost/ghost/).